n=eval(input())
m=input()
list1=list(m)
k=''
for i in list1:
    if 65<=ord(i)<=90:
        i=chr((ord(i)-65+n)%26+65)
    elif 97<=ord(i)<=122:
        i=chr((ord(i)-97+n)%26+97)
    else:
        pass
    k=k+i
print(k)
